This specification relates in general to simulating skin deformation relative to a muscle, for example, simulating sliding of a skin representation over a muscle representation.
Projects that rely on generating animations, such as the development of online applications (e.g., video game titles) and/or off-line applications (e.g., animated film productions), may call for a significant number of animations with varying levels of details. For example, animated characters located in the foreground of a particular scene may require a significant amount of detail to appear realistic and hold the attention of a casual viewer, whereas animated characters or other objects in the background typically can include less detail while still maintaining an appropriate level of realism.
To enhance the realism of a character's appearance, a skin representation can be overlapped over the character's bone structure such that the skin representation can move and bend alone with, but independently of, the character's limbs, torso, and the like. To help ensure that the skin representation deforms realistically when the bones are moved, bones of the character's skeleton can be assigned corresponding “influence volumes”—that is, defined portions of the skin representation that move with the respective bones.
To further enhance the realistic aspect of the character's appearance, a muscle representation can be added to the character's skeleton, and the skin representation can be configured. to move and deform in response to movement and deformation of the underlying muscle representation's geometry. For example, flexing a bicep muscle representation would deform a portion of the skin representation to conform to the shape of the bulged bicep muscle representation.